1. Field of the Invention
The present invention relates to an image processing apparatus and image processing method, which process paper fingerprint information that represents a fiber pattern unique to a paper sheet, a program, and a storage medium.
2. Description of the Related Art
In recent years, with the prevalence of multi-function image processing apparatuses, the importance for security is growing. Such multi-function image processing apparatus are convenient, but they may cause leakage of confidential information and illegal document forgery depending on its use method. For this reason, a multi-function copying machine includes a forgery prevention device, copy guard function, and the like. Also, a technique which identifies features of paper itself and guarantees the uniqueness and originality of a document based on the identified features (e.g., see patent reference 1: Japanese Patent Laid-Open No. 2004-102562) has been developed.
Using the technique disclosed in patent reference 1, paper sheets can be identified one by one by identifying a fiber pattern unique to each paper sheet. However, upon giving priority to the ease and certainty of verification, the collection position of a fiber pattern (to be referred to as a paper fingerprint hereinafter) to be identified is fixed, thus posing a problem. Furthermore, when paper fingerprints are to be collected at a fixed position, the verification ratio decreases if a character or image is printed at that position upon verification.
To solve this problem, a method of specifying the collection position by forming a specific mark at the collection position in advance has been proposed. However, since the paper fingerprint position is specified by that mark, it is not preferable in terms of security since it is easy to falsify by cutout, pasting, blindfold, and the like.